Sun Yang took China's first-ever men's Olympic gold in the pool with a last-length dash to beat Korea's defending champion Park Taehwan in the 400 meter freestyle final.
Sun, the world champion in the 800 meters and 1,500 meters, trailed Park until the final turn, kicking himself into an unassailable lead and cruising home.
"In training I've been working on the final 200 metres of the race," he said of his explosive finish.
"I used my speed to fly past the Korean."
Had Sun timed his finish better, he might have taken Paul Biedermann's world record of 3 minutes 40.07 seconds, set in Rome in 2009.
He finished five hundredths of a second off the record, with Park two seconds behind and America's double Olympic champion Peter Vanderkaay another two seconds adrift.
Park had earlier been disqualified from the event for an alleged false start in the heats, before being reinstated by an emergency meeting of swimming officials.
